1. Field
The present disclosure relates to ram fans for use in electronics cooling systems, more specifically to cooling systems for ram fan motors.
2. Description of Related Art
A ram air fan can be disposed in ram air cooling systems (e.g., for aircraft) that are designed to provide airflow over a liquid/air heat exchanger to make up for insufficient ram air, e.g., when a vehicle is moving at a low airspeed, to consistently remove enough heat from the liquid/air heat exchanger. Such heat exchangers can allow the removal of heat from a coolant inside a liquid cooling circuit (e.g., used to cool aircraft electronics).
The motor of the ram air fan itself requires cooling, and is traditionally cooled by ram air traveling from a ram inlet header, through a cooling duct, and into a motor housing to remove heat from the ram air fan motor. The flow is then ejected forward of the fan to rejoin exhaust flow from the from the liquid/air heat exchanger. Since this flow is induced by the ram air fan, such as when an aircraft is at low airspeed, the heat removal due to this induced cooling duct flow is small and can lead to the motor overheating in certain conditions. Also, fine object debris (FOD) that is taken in by the ram air inlet can clog the cooling duct and/or travel to the motor housing and clog airflow therethrough.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved cooling systems for ram air fan motors. The present disclosure provides a solution for this need.